BLC2, a wonderful powder in the 9.3x62, is also a great powder in the 9.3x57.
The overall loaded length is VERY important as it greatly changes the velocities, but more importantly, the pressure generated.
All of my loads showed VERY low pressure in my M46 Husky (M94action)

270gr. 50.0gr. BLC2 - 2,111fps
270gr. 53.0gr. BLC2 - 2,300fps - 3.070" OAL
225gr. 56.0gr. BLC2 - 2,550fps - 2.990" OAL
232gr. 56.0gr. BLCs - 2.450fps - 2.990" OAL

for example:
232gr. Norma Vulcan - 50.0gr. H4895 - 2,442fps - 2.865" OAL
232gr. Norma Vulcan - 52.0gr. H4895 - 2,436fps - 2.990" OAL

These rifles have long freebores or leades or whatever you want to call the long chamber throat.
Im most rifles, you cannot seat the bullet out far enough to get close to the rifling lands. The more deeply you seat the bullet, the smaller you make the powder chamber, the higher the pressure and velocity - however - the further out you can seat the bullet, the greater the case capacity, the larger the expansion ratio - the lower the velocity and pressure, but usually the better the accuracy.

Thus it might take a 2 or 3 grains more powder to duplicate the speeds of the 'shorter' load, but they will usually be more accurate.

IMR4064 can, of course be used in this ctg. Some guys also use IMR3031, however I feel it's a bit on the fast side.

The reason some of these rifles have oversized bores and chambers, is there never was a REAL CIP law for this round.

Norma loads their ammo to something akin to 34,000PSI. These rifles, both 98's and 94 actions are also chambered for the 6.5x55 = 55,000spi, along with the 7x57, 8x57 and 9.3x62- all 57,00psi rounds. Has anyone ever heard of a .30/06 Husky on a M98 action?- that's 60,000psi and the M94 Huskys are also chambered in '06. The M98's of course are also chambered in .243, 6mm and .270 - 65,000psi rounds.

So- Do I load my 9.3x57 M46 (94 action) to 60,000psi - no but I also do not limit myself to exceptionally low pressures either.

My rifle has .019" headspace, which is excessive. If you fire a soft load, or merely fire a primed empty case and the primer sticks out - you have excessive headspace. This has nothing to do with the action used, it is a function of not having any CIP law on case body length. In the States, there is a standard, SAAMI, but it is not LAW. In Europe, CIP is LAW. There never was a LAW governing the 9.3x57- for some unknown reason.

My data above, produced in new 8x57 RP brass necked straight, then necked in the FL die to produce a false shoulder then fireformed, produces ammo that has "0" headspace. It also produces "0" case web expansion - up to 2.5 tenthousandths of an inch (1/4 of a thousandths) - yes - .00025" - not .0025 which would be 2 1/2 thousandths).

Here's the process:--necked over 9.3 expander button in FL die - 0 losses
--------------------necked straight - 1 pass - 0 losses.
---------------necked for crush fit - 1 pass into FL die 0 losses

fireformed with normal load - sub MOA accuracy and 0 losses. The brass is just about perfectly formed in the FL die.

No ANNEALING necessary.